Internal needle

ABSTRACT

An indwelling needle is provided which has a simple structure and is capable of securely mounting a needle tip protective tool on the tip portion of an internal needle. The indwelling needle A consists of an external needle  10  including a cannula  11  and a housing  12 , an internal needle  20  including a metal needle  21  and a hub  22  and a needle tip protective tool  30 . The needle tip protective tool  30  is mounted on the housing  12  with the metal needle  21  inserted into an inner section so that the metal needle  21  can be removed together with the internal needle  20  from the external needle  10 . A main body  31  of the needle tip protective tool  30  has a cylindrical shape. Window sections  34   a , 34 b  are provided on opposing circumferential surfaces of the main body  31 . On a rear end marginal section of window section  34   a , a movable gripped section  32  is provided whose outer section  32   b  extends toward the outside of the main body  31  and whose end consists of a grip section  32   c . The gripped section  32   c  and the grip section  33   c  are latchable with each other within main body  31.

This application is a U.S. National application of PCT/JP2006/324128filed on Nov. 11, 2006, which claims priority to Japanese PatentApplication No. 2005-341866 filed on Nov. 28, 2005, the contents of bothare incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Technical Field

The present disclosure pertains to a type of indwelling needle that isused in transfusion and blood collection for piercing and indwelling ina blood vessel of a patient.

2. Background of Related Art

In the prior art, indwelling needles have been used in variousapplications, such as hemodialysis or feeding of prescribed medicinesolutions, etc. The indwelling needle includes an external needle havinga needle tip for indwelling in a blood vessel of a patient and aninternal needle that is inserted into the external needle to facilitatesmooth piercing of the blood vessel of the patient. In operation, theinternal needle is inserted into the external needle such that the tipportion of the internal needle protrudes from the tip portion of theexternal needle. Thereafter, together with the internal needle, theexternal needle pierces the blood vessel. Then, while the externalneedle indwells in the blood vessel, the internal needle is pulled outof the external needle (blood vessel), and a tube member or the like forfeeding prescribed blood or medicine solution or the like is connectedto the rear end portion of the external needle, and hemodialysis orfeeding of a medicine solution or the like is carried out.

In the indwelling needle, there is a needle tip protective part forpreventing the patient from being harmed by the needle tip of theinternal needle which is pulled out of the external needle. The needletip protective part has a tapered cylindrical body with an innerdiameter larger on one end and smaller on the other end. The tip portionof the internal needle protected by the needle tip protective part isformed of a size that permits it to be inserted into the opening on oneend of the needle tip protective part but not into the opening on theother end. Consequently, when the internal needle is pulled through theneedle tip protective part, the tip end of the internal needle cannotpass through the opening on the other end of the needle tip protectivepart. Thus, the needle tip protective part is coupled to the tip portionof the internal needle and the tip portion of the internal needle iscovered.

However, the aforementioned needle tip protective part of the prior artis prone to shifting position to the rear side of the internal needle.Consequently, the tip portion of the internal needle may be exposed.People have proposed a type of indwelling needle having a needle tipprotective part that makes use of a spring member or the like to fix theprotective part at the tip portion of the internal needle so that thetip portion of the internal needle can be reliably covered. However, forthe indwelling needle, the number of parts increases, the manufacturingcost rises, and the resistance when the internal needle is pulled out ofthe external needle becomes higher, leading to poor operability. This isundesirable.

The purpose of the present disclosure is to solve the aforementionedproblems of the prior art by providing a type of indwelling needle thathas a simple structure, good operability, and can have the needle tipprotective part mounted reliably on the tip portion of the internalneedle.

SUMMARY

An indwelling needle is provided which includes an outer cannula forindwelling placement in a patient. The cannula has a housing attached toa proximal end thereof. An inner needle has a connection part at aproximal end thereof. A needle tip protector is positioned within thehousing and around the inner needle. The needle tip protector comprisesa first portion having a sidewall defining a through-hole of a firstdiameter and a second portion having a sidewall defining a through-holeof a second diameter, which is smaller than the first diameter. Thesidewall of the first portion comprises at least one inwardly movableblocking member attached thereto. The inner needle has a tip portion anda main portion. The tip portion has a larger diameter than the mainportion. The tip portion, the main portion and the second portions aredimensioned such that the main portion but not the tip portion isslidable through the through-hole of the second portion. The indwellingneedle is configured such that withdrawing the inner needle from thecannula in a proximal direction causes the tip portion to engage withthe second portion, thereby withdrawing the needle tip protector fromthe housing and causing the at least one blocking member to moveinwardly into the first portion through-hole so as to trap the tipportion therein.

In one embodiment the needle tip protector comprises at least twoblocking members which can be diametrically opposed to one another. Thehousing and the blocking members can be shaped such that on withdrawingthe inner needle, the housing is arranged to exert inward pressure onthe blocking members to cause inward movement thereof.

In one embodiment the blocking members are attached to the needle tipprotector first portion sidewall at a proximal end of the blockingmember. The blocking members can have distal ends formed to provide alocking action when mutually engaged.

In one embodiment, the needle tip protector further comprises a slipring arranged such that on withdrawal of the inner needle, the slip ringis caused to slide over the blocking members to move the blockingmembers inwardly. The blocking members can be attached to the needle tipprotector first portion sidewall at a proximal end of the blockingmember. The blocking members can have distal ends formed to provide alocking action when mutually engaged. In one embodiment, the blockingmembers are attached to the needle tip protector first portion sidewallat a distal end of the blocking member. In one embodiment, two of saidblocking members have proximal ends forming a tongue and grooveinterrelation.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will now be described, by way of example only,with reference to the accompanying drawings in which:

FIG. 1 shows the indwelling needle of Embodiment 1 (a) is a side view,and (b) is a front view;

FIG. 2 is a cross-sectional view of the indwelling needle;

FIG. 3 is a cross-sectional view illustrating the state in which theinternal needle is being pulled out of the external needle, and themovable held portion is energized to the main body side;

FIG. 4 is a cross-sectional view illustrating the state in which theinternal needle is being pulled out of the external needle, and themovable holding portion is energized to the main body side;

FIG. 5 is a cross-sectional view illustrating the state in which theinternal needle has been pulled from the external needle;

FIG. 6 illustrates the needle tip protective part in the indwellingneedle in Embodiment 1.

FIG. 6( a) is a plane view; (b) is a side view; (c) is a front view; (d)is an inner side view; and (e) is a bottom view;

FIG. 7 is a cross-sectional view taken across 7-7 in FIG. 6( a);

FIG. 8 illustrates the state in which the held portion and holdingportion of the needle tip protective part shown in FIG. 6. (a) is aplane view; (b) is a side view; (c) is a front view; (d) is an innerside view; and (e) is a bottom view;

FIG. 9 is a cross-sectional view taken across 9-9 of FIG. 8( a);

FIG. 10 is a cross-sectional view of the indwelling needle in Embodiment2 of the present disclosure;

FIG. 11 is a cross-sectional view illustrating the state in which theinternal needle is being pulled from the external needle of theindwelling needle shown in FIG. 10, and the held portion and the holdingportion grip each other;

FIG. 12 is a cross-sectional view illustrating the state in which theinternal needle has been pulled from the external needle of theindwelling needle shown in FIG. 10;

FIG. 13 illustrates the needle tip protective part of the indwellingneedle in Embodiment 2. (a) is a plane view; (b) is a side view; (c) isa front view; (d) is an inner side view; (e) is a bottom view;

FIG. 14 is a cross-sectional view taken across 14-14 in FIG. 13( a);

FIG. 15 illustrates the state in which the held portion and holdingportion of the needle tip protective part shown in FIG. 13 grip eachother, (a) is a plane view; (b) is a side view; (c) is a front view; (d)is an inner side view; (e) is a bottom view;

FIG. 16 is a cross-sectional view taken across 16-16 of FIG. 15( a);

FIG. 17 is a cross-sectional view of the indwelling needle in Embodiment3 of the present disclosure;

FIG. 18 is a cross-sectional view illustrating the state after theinternal needle is being pulled out of the external needle in theindwelling needle shown in FIG. 17;

FIG. 19 is a cross-sectional view illustrating the state after theinternal needle has been pulled out of the external needle in theindwelling needle shown in FIG. 17;

FIG. 20 illustrates the needle tip protective part of the indwellingneedle in Embodiment 3. (a) is a plane view; (b) is a side view; (c) isa front view; (d) is an inner side view; (e) is a bottom view;

FIG. 21 is a cross-sectional view taken across 21-21 in FIG. 20( a);

FIG. 22 illustrates the state in which the gripping pieces of the needletip protective part shown in FIG. 20 have entered the main body, (a) isa plane view; (b) is a side view; (c) is a front view; (d) is an innerside view; (e) is a bottom view;

FIG. 23 is a cross-sectional view taken across 23-23 in FIG. 22( a);

FIG. 24 is a diagram illustrating the needle tip protective part of theindwelling needle in Embodiment 4. (a) is a plane view; (b) is a sideview; (c) is a front view; (d) is an inner side view; (e) is a bottomview;

FIG. 25 is a cross-sectional view taken across 25-25 of FIG. 24( a);

FIG. 26 is a side view illustrating the state in which the ring-shapedmember is positioned on the rear side of the main body;

FIG. 27 is a side view illustrating the state in which the ring-shapedmember is moved to the front side of the main body, and one movablegripped part is energized in the main body;

FIG. 28 is a side view illustrating the state in which the ring-shapedmember is moved to the front side of the main body, and the pair ofmovable gripped parts are energized in the main body;

FIG. 29 is a side view illustrating the state in which the ring-shapedpart is further moved, and the pair of movable gripped parts areenergized in the main body;

FIG. 30 is a side view illustrating the state in which the ring-shapedpart is made to pass through the portion corresponding to the pair ofmovable gripped parts in the main body, and the pair of movable grippedparts is gripped; and

FIG. 31 is a side view illustrating the state in which the ring-shapedmember is moved to the front side of the main body, and the grippingstate of the pair of the movable gripped parts is maintained.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following, a detailed explanation will be given regardingembodiments of the indwelling needle of the present disclosure withreference to the figures. FIGS. 1-5 illustrate indwelling needle A inembodiment 1 of the present disclosure. Indwelling needle A is composedof an external needle (10) that indwells in the blood vessel of thepatient, an internal needle (20) that can be inserted into the interiorof external needle (10) and has a sharp tip portion which can pierce thebody of the patient, a suction part (25) mounted on the rear portion ofinternal needle (20), and a needle tip protective part (30) forprotecting the tip portion of internal needle (20). External needle (10)is composed of a fine tubular cannula (11), and a housing (12) which isconnected to the base end portion of cannula (11). Throughout thisdescription, the right hand side in FIG. 1 refers to the rear endportion, the tip side (left hand side) of cannula (11) will be referredto as the front side, and the base end side (right hand side) of cannula(11) will be referred to as the rear side.

Cannula (11) has an internal cavity (13) that forms the flow channelthat goes from the tip portion (11 a) through to the rear end portion(11 b). On the outer peripheral surface of tip portion (11 a) of cannula(11), a taper is formed with the front end side tapered finer. Also,rear end portion (11 b) of cannula (11) gradually widens. Cannula (11)indwells in the blood vessel of the patient for withdrawing blood fromthe blood vessel, or for feeding medicine solutions, etc., into theblood vessel. Housing (12) is composed of a housing front portion (12 a)which is fixed on rear end portion (11 b) of cannula (11), and a housingrear portion (12 b) that forms the rear side portion of housing (12) andhas a substantially cylindrical shape.

The front end portion of housing front portion (12 a) has a slendershape with a smooth surface formed between the housing front portion (12a) and rear end portion (11 b) of cannula (11). The front side portionof housing rear portion (12 b) has the same diameter as that of the rearend portion of housing front portion (12 a). Opening portion (14) formsthe rear side of housing rear portion (12 b) and has a smaller diameterthan the front side portion of housing rear portion (12 b) and a largerdiameter than the front end portion of housing front portion (12 a). Inaddition, opening portion (14) has a female luer syringe shape with adiameter gradually increasing from the front to the rear. The portionbetween the front side portion of housing rear portion (12 b) andopening portion (14) is formed in a cylindrical shape with the diameterdecreasing toward the rear side.

The interior of housing (12) defines a space (15 a) with a larger innerdiameter from the front side portion to nearly the central portion alongthe axial direction, and a space (15 b) with a smaller inner diameter inthe rear side portion. The portion of the inner peripheral surface ofhousing (12) between space (15 a) gradually increases in diameter fromthe front portion to the rear portion along the housing front portion(12 a).

Internal needle (20) is composed of metal needle (21) which is made ofstainless steel and a hub (22) fixed on a base end portion of metalneedle (21). In one embodiment, metal needle (21) is made of a finetubular injection needle, with front end portion (21 a) cut oblique withrespect to the axial direction to form a sharp tip portion. The frontside portion of metal needle (21) has a larger diameter than the rearside portion of metal needle (21). A step (21 b) is formed at a boundaryportion between the front side portion and the rear side portion of themetal needle (21). Metal needle (21) is configured to ensure smoothinsertion when tip portion (11 a) of cannula (11) is inserted into apatient's blood vessel. Metal needle (21) is inserted into externalneedle (10) from the rear end portion of external needle (10), such thatfront end portion (21 a) protrudes out of the opening of tip portion (11a) of cannula (11) for use. Front end portion (21 a) of metal needle(21) passes through the interior of housing (12) and the interior ofcannula (11), and protrudes out of tip portion (11 a) of cannula (11).

Hub (22) is fixed on metal needle (21) such that the outer peripheralportion of the rear end portion of metal needle (21) is covered. Hub(22) includes a hub main body (22 a) which is fixed to metal needle(21), and a cylindrical mounting portion (22 b) which is formed on rearside of hub main body (22 a) and has a recess opening towards the rearside. Mounting portion (22 b) has a female luer syringe shape whichgradually becomes larger from the front side to the rear side.

A flange-shaped collar portion (23) is formed on the front endperipheral portion of hub main body (22 a). Metal needle (21) is bondedand fixed via bonding portion (24) to hub main body (22 a). In oneembodiment, suction part (25) is a syringe which includes a piston part(27) which is inserted in a cylinder part (26) that can accommodate gasor liquid. A male luer syringe tip portion (28) that forms the tipportion of cylinder part (26) is inserted into mounting portion (22 b)of hub (22) to assemble suction part 25 on internal needle (20).

Needle tip protective part (30) is set in housing (12) of externalneedle (10). As shown in FIGS. 6-9, needle tip protective part (30) iscomposed of main body (31) and a pair of movable gripped parts includinga movable held part (32) and movable holding part (33). Main body (31)is formed in a cylindrical shape. The inner peripheral portion of therear end portion of tip protective part 30 has a small diameter portion(31 a). A step is formed between small diameter portion (31 a) and afront side inner peripheral surface (31 b) of tip protective part 30.This small diameter portion (31 a) has a diameter which is smaller thanthe diameter of the tip side portion of metal needle (21) yet allowspassage of the remaining portion of metal needle (21).

Window portions (34 a), (34 b) extend in the axial direction along mainbody 31 at positions which are slightly axially offset (FIG. 7) anddiametrically opposed. Window portions (34 a), (34 b) are each formed asholes having a larger width at the front side and a smaller width at therear side. Base end portion 32 a of movable held part (32) is connectedby a hinge to the rear end edge portion of window portion (34 a), andbase end portion (33 a) of movable holding part (33) is connected by ahinge to the rear end edge portion of window portion (34 b). In thestate shown in FIGS. 6 and 7, when needle tip protective part (30) isset in housing (12) of external needle (10), outer side portion (32 b)of movable held part (32) protrudes towards the outer side along slopesurface (16) of housing (12). Held portion (32 c) of tip protective part(30) diverges outwardly from base end portion (32 a), and the innersurface of held portion (32 c) includes a protrusion that protrudestowards the inner side of main body (31).

In the state shown in FIGS. 6 and 7, when needle tip protective part(30) is set in housing (12), outer side portion (33 b) of movableholding part (33) is positioned along slope surface (16) of housing (12)and holding portion (33 c) of tip protective part (30) divergesoutwardly from base end portion (33 a). A pair of protrusions is formedon the inner surface of holding portion (33 c). The protrusions protrudetowards the inner side of main body (31), and can be fixed by holdingheld portion (32 c) of movable held part (32) from the front and back.In the state shown in FIGS. 6 and 7, metal needle (21) can be insertedthrough the portion inside needle tip protective part (30) correspondingto movable held part (32) and movable holding part (33).

When metal needle (21) is positioned inside needle tip protective part(30), held portion (32 c) and holding portion (33 c) are in contact withthe outer peripheral surface of metal needle (21), and outer sideportion (32 b) of movable held part (32) and outer side portion (33 b)of movable holding part (33) protrude outwardly of main body (31). Whenouter side portion (32 b) and outer side portion (33 b) are pressed intothe inner side of main body (31) such that the outer surface of outerside portions (32 b) and (33 b) are aligned with the peripheral surfaceof main body (31), as shown in FIG. 9, held portion (32 c) and holdingportion (33 c) grip or engage each other.

When metal needle (21) of internal needle (20) passes through needle tipprotective part (30) set in housing (12) of external needle (10), andthe rear end side of metal needle (21) is positioned inside needle tipprotective part (30), front end portion (21 a) of metal needle (21)extends from tip portion (11 a) of cannula (11). In this case, collarportion (23) of internal needle (20) comes into contact with the rearend of opening portion (14) of housing (12) of external needle (10).

When indwelling needle A is inserted into a patient, front end portion(21 a) of metal needle (21) and tip portion (11 a) of cannula (11) shownin FIG. 1 are simultaneously pushed to pierce a portion of the patient,such as the wrist, to reach a blood vessel. Then, piston part (27) ofsuction part (25) which is attached on the rear portion of hub (22) ispulled back from cylinder part (26). As a result, the blood in the bloodvessel is drawn into metal needle (21), and it enters the portion inmetal needle (21) corresponding to hub main body (22 a) of hub (22).Then, the blood is drawn into cylinder part (26). As a result, the colorbecomes red inside hub (22) and cylinder part (26), and the operator canverify that front end portion (21 a) of metal needle (21) has reachedthe blood vessel.

While internal needle (20) is maintained within the blood vessel,external needle (10) is pressed forward a little, so that tip portion(11 a) of external needle (10) further enters the front portion withinthe blood vessel. Then, as shown in FIG. 3, internal needle (20) ispulled toward the rear side of external needle (10) with suction part(25). As this occurs, metal needle (21) is pulled from cannula (11) andfront end portion (21 a) of metal needle (21) is withdrawn inside needletip protective part (30) and housing (12). Then, together with suctionpart (25), internal needle (20) is pulled from the rear side of externalneedle (10). When step (21 b) of metal needle (21) engages smalldiameter portion (31 a) of needle tip protective part (30), metal needle(21) and needle tip protective part (30) engage each other.

When needle tip protective part (30) engages the front end portion ofmetal needle (21), internal needle (20) together with suction part (25)and tip protective part (30) are withdrawn from external needle (10). Astip protective part (30) is withdrawn from housing (12) of externalneedle (10), movable held part (32) and movable holding part (33) moveinto engagement with slope surface (16) of housing (12) and are urgedinwardly into main body (31) of tip protective part (30). As tipprotective part (30) is moved from the rear end of housing (12), movableheld part (32) moves towards movable holding part (33) as shown in FIG.3

When movable held part (32) and movable holding part (33) pass overslope surface (16) and enter space (15 b) of housing (12), held portion(32 c) and holding portion (33 c) engage each other entirely. In thiscase, held portion (32 c) of movable held part (32) and/or holdingportion (33 c) of movable holding part (33) are flexible, and, as theflexible portions bend, held portion (32 c) and holding portion (33 c)can lockingly engage each other as shown in FIGS. 4 and 9.

As internal needle (20) is pulled further rearwardly with suction part(25) to the rear side of external needle (10), needle tip protectivepart (30) engages the tip of metal needle (21), and internal needle (20)is withdrawn together with suction part (25) from external needle (10)as shown in FIG. 5. In this case, front end portion (21 a) of metalneedle (21) is positioned between small diameter portion (31 a) ofneedle tip protective part (30) and the portion of needle tip protectivepart (30) where held portion (32 c) and holding portion (33 c) lockinglyengage each other. Consequently, tip protective part (30) is retained onfront end portion (21 a) of metal needle (21) and the likelihood ofneedle stick injury is minimized.

After internal needle (20) has been removed from external needle (10), aconnecting portion of a tube member (not shown) which extends from afeeding device (not shown) for medicine solution or the like isconnected to opening portion (14) of housing (12). In this way, whilethe tube member is connected to housing (12), the feeding device candeliver medicine solution, etc., to the blood vessel. Internal needle(20) which is pulled out of external needle (10) is discarded at aprescribed site.

In summary, needle tip protective part (30) includes a cylindrical mainbody (31), a movable held part (32) and a movable holding part (33).Movable held part (32) and movable holding part 33 are connected by ahinge to the edge portions of window portions (34 a), (34 b) set facingeach other on the peripheral surface of main body (31). When metalneedle (21) is retracted through needle tip protective part (30),movable held part (32) and movable holding part (33) are urged inwardlytowards the outer side of main body (31) by slope surface (16) ofhousing 12 of internal needle (10). The structure is such that whenneedle tip protective part (30) is pulled out of housing (12), heldportion (32 c) of movable held part (32) and holding portion (33 c) ofmovable holding part (33) grip or lockingly engage each other, and thefront end portion of main body (31) of tip protective part (30) isobstructed. Thus, even when needle tip protective past (30) is moved tothe rear side of internal needle (20) so that front end portion (21 a)of needle 21 is exposed, by bringing front end portion (21 a) intocontact with the gripping portion between held portion (32 c) andholding portion (33 c), front end portion (21 a) of needle (21) isprevented from becoming exposed.

The resistance to internal needle (20) is the only reactive force actingfrom slope surface (16) of housing (12) when movable held part (32) andmovable holding part (33) are urged into main body (31). Consequently,smooth operation can be performed. Also in this case, it is onlyrequired that movable held part (32) and movable holding part (33) beconnected in a rotatable way to the edge portions of window portions (34a), (34 b), so that the connection can be performed even without elasticand other characteristics. Also, movable held part (32) and movableholding part (33) can be formed integrally to main body (31) by means ofintegrated molding. Consequently, the structure of needle tip protectivepart (30) becomes simpler, and manufacturing can be performed easily andwith a high stability.

Embodiment 2

FIGS. 10-12 illustrate indwelling needle B in Embodiment 2 of thepresent disclosure. For this indwelling needle B, housing (42) ofexternal needle (40) includes a housing front portion (42 a) that formsthe front side portion of housing (42) and housing rear portion (42 b)that forms the rear side portion of housing (42). Housing (42) has asubstantially cylindrical shape. The interior of housing (42) defines aspace (45 a) with a larger inner diameter between the front side portionof housing front portion (42 a) to nearly the center of housing rearportion (42 b). The rear side portion of housing (42) defines a space(45 b) with an inner diameter smaller than that space (45 a) of thefront side portion. Space (45 b) is formed such that its inner diametergradually increases from the front side to the rear side. A taperedslope surface (46), short in the axial direction, is formed betweenspace (45 a) and space (45 b) on the inner peripheral surface of housing(42).

As shown in FIGS. 13-16, needle tip protective part (50) of indwellingneedle B is composed of main body (51), a movable held part (52) and amovable holding part (53). Main body (51) has a cylindrical shape, andthe inner peripheral surface of its rear end portion (the end portionpositioned on the rear end opening side when it is set in housing (42))is formed with a diameter smaller than the remaining portion to formsmall diameter portion (51 a). A step is formed between small diameterportion (51 a) and the remaining front-side peripheral surface (51 b).Window portions (54 a), (54 b) extend in an axial direction on main body51 and are diametrically opposed to each other at a location a littleahead of the center in the axial direction of main body (51). Bothwindow portions (54 a), (54 b) are formed as rectangular holes.

Base end portion (52 a) of movable held part (52) is connected by ahinge to the front end edge portion of window portion (54 a), and baseend portion (53 a) of movable holding part (53) is connected by a hingeto the front end edge portion of window portion (54 b). In the stateshown in FIGS. 13 and 14, outer side portion (52 b) of movable held part(52) protrudes outwardly from main body (51) along slope surface (46) ofhousing (42). Held portion (52 c) of the rear end (free end) is formedas a protrusion with a width which is narrower than that of movable heldpart (52).

In the state shown in FIGS. 13 and 14, outer side portion (53 b) ofmovable holding part (53) protrudes outwardly from main body (51)towards slope surface (46) of housing (42). Holding portion (53 c) onthe rear end of movable holding part (53) is formed as a pair ofprotrusions formed by providing a recess that has the rear side andupper/lower sides open at the center in the width direction. Thisholding portion (53 c) is formed such that held portion (52 c) ofmovable held part (52) can be received and retained in the recess inholding portion (53 c). As shown in FIGS. 14 and 16. The structure ofthe remaining portion of indwelling needle B is the same as that inindwelling needle A. Consequently, the same part numbers as thoseadopted for indwelling needle A are adopted, and they will not beexplained again.

When indwelling needle B is in use, the same operation as that forindwelling needle A is performed. In this case after front end portion(21 a) of metal needle (21) is inserted through tip portion (11 a) ofcannula (11) in indwelling needle B as shown in FIG. 10, cannula (11)and needle (21) are simultaneously pushed to pierce the wrist of thepatient to reach the blood vessel. Next, external needle (10) is pusheda little more to the front side so that tip portion (11 a) of externalneedle (10) reaches the blood vessel. While tip portion (11 a) ofexternal needle (10) indwells in the blood vessel of the patient asshown in FIG. 11, internal needle (20) is pulled towards the rear sideof external needle (10) together with suction part (25). Metal needle(21) is withdrawn from cannula (11) and front end portion (21 a) ofmetal needle (21) is positioned in needle tip protective part (50) inhousing (42). Then, internal needle (20) is pulled towards the rear sideof external needle (40) such that step (21 b) of metal needle (21) andsmall diameter portion (51 a) of needle tip protective part (50) engageor grip each other.

Together with suction part (25), internal needle (20) is pulled back tothe rear side of external needle (10). As a result, while needle tipprotective part (50) engages the front end portion of metal needle (21),internal needle (20) is withdrawn together with suction part (25) fromexternal needle (10). When metal needle (21) is still positioned in theportion inside needle tip protective part (50) corresponding to movableheld part (52) and movable holding part (53), by means of metal needle(21), movable held part (52) and movable holding part (53) are urgedinwardly of main body (51) as they move along slope surface (46) withinhousing (42). As needle tip protective part (50) engages metal needle(21), metal needle (21) and needle tip housing are withdrawn fromhousing (42). As a result, outer side portion (52 b) of movable heldpart (52) and outer side portion (53 b) of movable holding part (53) areurged by slope surface (46) towards the inner side of main body (51) asshown in FIG. 11.

When movable held part (52) and movable holding part (53) move overslope surface (46) and enter space (45 b) of housing (42), held portion(52 c) and holding portion (53 c) are engaged. Then, as internal needle(20) is withdrawn with suction part (25) to the rear side of externalneedle (10), while needle tip protective part (50) is engaged with thetip of metal needle (21), internal needle (20) is withdrawn with suctionpart (25) from external needle (10) as shown in FIG. 12. Thereafter, aconnecting portion of a tube member extending from a feeding device fordelivering medicine solution or the like is connected to opening portion(14) of housing (42). In this way, the feeding device which is connectedto the base end portion of the internal needle can operate to delivermedicine solution, etc., to the blood vessel.

Referring to FIGS. 13-14, held portion (52 c) is formed on the rear endportion of movable held part (52), and holding portion (53 c) is formedon the rear end portion of movable holding part (53). Consequently, thedistance between the portion where held portion (52 c) and holdingportion (53 c) are engaged and the front end portion of main body (51)becomes longer and front end portion (21 a) of metal needle (21) movesaway from the front end portion of main body (51). As a result, frontend portion (21 a) of metal needle (21) can barely exit the front endportion of needle tip protective part (50). Also, when needle tipprotective part (50) is moved to the rear side of internal needle (20)so as to expose front end portion (21 a) of metal needle (21), front endportion (21 a) of metal needle (21) presses the gripped portion betweenheld portion (52 c) and holding portion (53 c), so that the grip betweenheld portion (52 c) and holding portion (53 c) is made stronger.Consequently, safety is further improved. The other functions andeffects of indwelling needle B are the same as those of the indwellingneedle A.

Embodiment 3

FIGS. 17-19 illustrate indwelling needle C in Embodiment 3 of thepresent disclosure. For indwelling needle C, as shown in FIGS. 20-23,needle tip protective part (60) is composed of main body (61) and a pairof movable gripped parts (62), (63). Main body (61) has a cylindricalshape, and the inner peripheral surface of its rear end portion isformed with a diameter smaller than the remaining portion to form smalldiameter portion (61 a). A step is formed between small diameter portion(61 a) and the remaining front-side peripheral surface (61 b). Windowportions (64 a), (64 b) which extend in an axial direction on main body(61) are formed in the portions facing each other at the site a littleahead of the center in the axial direction of main body (61). Bothwindow portions 64 a, 64 b are formed as tapered holes wider in frontand narrower toward the rear.

Base end portion (62 a) of movable held part (62) is connected by ahinge to the rear end edge portion of window portion (64 a), and baseend portion (63 a) of movable holding part (63) is connected by a hingeto the rear end edge portion of window portion (64 b). As shown in FIGS.20 and 21, outer side portion (62 b) of movable held part (62) protrudesoutwardly from main body (61). A flexible planar shaped gripping piece(62 c) is formed on the front end (free end) of movable gripped part(62). In the state shown in FIGS. 20 and 21, outer side portion (63 b)of movable holding part (63) protrudes outwardly of main body (61). Onthe front end (free end) of movable gripped part (63), a flexibleplanar-shaped gripping piece (63 c) is formed.

When the pair of movable gripped parts (62), (63) is urged towards theinner side of main body (61), the parts (62), (63) are bent while incontact with the front end edge portions of window portions (64 a), (64b). The structure is such that, after gripping pieces (62 c), (63 c)enter main body (61), gripping pieces (62 c), (63 c) are obstructed fromexiting the main body (61) by engagement with the front edge portions ofwindow portions (64 a), (64 b). The structure of the remaining portionof the indwelling needle C is the same as that in indwelling needle A.Consequently, the same part numbers as those adopted for indwellingneedle A are adopted, and they will not be explained again.

Indwelling needle C is used in a manner substantially similar toindwelling needle A as described above. Just as in the Embodiments 1 and2, tip portion (11 a) of external needle (10) indwells in the bloodvessel of the patient in the state shown in FIG. 17. Thereafter,internal needle (20) is pulled together with suction part (25) to therear side of external needle (10) as shown in FIG. 18. After front endportion (21 a) of metal needle (21) is positioned in needle tipprotective part (60) in housing (42), internal needle (20) is pulledtowards the rear side of housing 12 such that step (21 b) of metalneedle (21) and the small diameter portion (61 a) of needle tipprotective part (60) grip or engage each other.

Then, internal needle (20) is pulled together with suction part (25)rearwardly in relation to external needle (10), while needle tipprotective part (60) engages the tip side portion of metal needle (21).When metal needle (21) is positioned in the portion inside needle tipprotective part (60) corresponding to movable gripped parts (62), (63),by means of metal needle (21), movable gripped parts (62), (63) aremoved along slope surface (16) within housing (12). Then, as needle tipprotective part (60) engages metal needle (21), metal needle (21) andprotective part (60) are withdrawn from housing (12). As a result, outerside portions (62 b), (63 b) of movable gripped parts (62), (63) areurged into main body (61) by slope surface (16).

As a result, gripping pieces (62 c), (63 c) contact the front end edgeportions of window portions (64 a), (64 b) and are bent (FIG. 21). Inthis state, gripping pieces (62 c), (63 c) enter main body (61) asinternal needle (20) is withdrawn with suction part (25) to the rearside of external needle (10), as shown in FIG. 19. Thereafter, aconnecting portion of a tube member extending from a feeding device canbe operated to deliver medicine solution or the like to opening portion(14) of housing (12). In this way, the feeding device can be operated todeliver medicine solution, etc., to a blood vessel.

For indwelling needle C, when gripping pieces (62 c), (63 c) of the pairof movable gripped parts (62), (63) engage the edge portions of windowportions (64 a), (64 b), the interior of main body (61) is obstructedwhile the gap formed between the pair of movable gripped parts (62),(63) becomes smaller than the diameter of metal needle (21).Consequently, there is no need to have the gripping pieces (62 c), (63c) grip each other, and the force for urging the pair of movable grippedparts (62), (63) into main body (61) can be small. The other functionsand effects of indwelling needle C are the same as those of indwellingneedle A as described above.

Embodiment 4

FIGS. 24 and 25 illustrate needle tip protective part (70) of theindwelling needle in Embodiment 4 of the present disclosure. The needletip protective part (70) is composed of main body (71) and a pair ofmovable gripped parts (72), (73). Main body (71) has a cylindricalshape, and the inner peripheral surface of its rear end portion (theright hand side end portion shown in FIGS. 24 and 25) is formed with adiameter smaller than the remaining portion to form small diameterportion (71 a). A step is formed between small diameter portion (71 a)and the remaining front-side peripheral surface (71 b). Window portions(74 a), (74 b) which extend in the axial direction on main body (71) areformed in the portions facing each other at a location a little ahead ofthe center of main body (71) in the axial direction of main body (71).Both window portions (74 a), (74 b) are formed as rectangular holes withdifferent lengths in the longitudinal direction. While these windowportions have front end portions positioned at the same site in theaxial direction, their rear end portions are located at differentpositions. More specifically, the rear end portion of window portion (74b) is positioned behind that of window portion (74 a).

Base end portion (72 a) of movable held part (72) is connected by ahinge to the rear end edge portion of window portion (74 a), and baseend portion (73 a) of movable holding part (73) is connected by a hingeto the rear end edge portion of window portion (74 b). Main body (76) ofthe gripping portion of movable gripped part (72) is composed of athicker portion (76 a) on the side of base end portion (72 a), and athinner portion (76 b) on the tip side. The width of thicker portion (76a) is selected to be smaller than that of window portion (74 a). Thewidth of thinner portion (76 b) is selected to be smaller than that ofwindow portion (74 a) such that thinner portion (76 b) is positionedalong the center of window portion (74 a) in the width direction.

Step (76 c) is formed at the boundary between thicker portion (76 a) andthinner portion (76 b) on one surface of main body (76) of the grippingportion. The thickness of thinner portion (76 b) is selected to be alittle smaller than half the thickness of thicker portion (76 a). Asshown in FIG. 26, outer side portion (72 b) of movable gripped part (72)protrudes outwardly of main body (71). A wedge-shaped grippingprotrusion (72 c) is formed on the surface on the side of step (76 c) inthinner portion (76 b) of the main body (76) of the gripping portion ofmovable gripped part (72).

Main body (77) of the gripping portion of movable gripped part (73) iscomposed of a thicker portion (77 a) on the side of base end portion (73a) and a thinner portion (77 b) on the tip side. The width of thickerportion (77 a) is selected to be a little smaller than that of windowportion (74 b). The width of thinner portion (77 b) is selected to besmaller than window portion (74 b) so that thinner portion (77 b) islocated at nearly the center of window portion (74 b) in the widthdirection. Step (77 c) is formed at the boundary portion between thickerportion (77 a) and thinner portion (77 b) on the other surface of mainbody (77) of the gripping portion. The thickness of thinner portion (77b) is selected to be a little smaller than half the thickness of thickerportion (77 a). As shown in FIG. 26, outer side portion (73 b) ofmovable gripped part (73) protrudes outwardly of main body (71) ofprotective tip (70). On the surface on the side of step (77 c) inthinner portion (77 b) of main body (77) of the gripping portion, awedge-shaped gripping protrusion (73 c) is provided that can be grippedor engaged by gripping protrusion (72 c) of movable gripped part (72).

On the outer peripheral surface of main body (71), a ring-shaped member(78) is attached such that it can move in the axial direction of mainbody (71). As shown in FIGS. 26-31, as ring-shaped member (78) is movedfrom the rear end side to the front end side of main body (71), movablegripped parts (72), (73) can pass through the interior of windowportions (74 a), (74 b) and can be pressed into main body (71). On therear end of housing (12) of the external needle (10) having needle tipprotective part (70) attached to it, a recess (not shown in the figure)for fixing ring-shaped member (78) is formed. The other features of thestructure of the indwelling needle having the needle tip protective part(70) are the same as those of the indwelling needle A, and the same partnumbers are adopted here.

The operation of movable gripped parts (72), (73) in the indwellingneedle having needle tip protective part (70) can be explained withreference to FIGS. 26-31. In use, ring-shaped member (78) is moved tothe front side of main body (71), as shown in FIG. 27. As a result,after the front end portion of ring-shaped member (78) comes intocontact with base end portion (73 a) of movable gripped part (73),movable gripped part (73) is pressed ahead. As a result, movable grippedpart (73) rotates around base end portion (73 a) and it enters main body(71). In this case, as shown in FIG. 27, thinner portion (77 b) andwedge-shaped gripping protrusion (73 c) of movable gripped part (73)move to enter the recess side portion of thinner portion (76 b) ofmovable gripped part (72).

When ring-shaped member (78) is moved further towards the front side ofmain body (71), after the tip portion of ring-shaped member (78) comesinto contact with base end portion (72 a) of movable gripped part (72),it presses movable gripped part (72) forward. As a result, movablegripped part (72) rotates around base end portion (72 a) and, as shownin FIG. 28, it enters main body (71). Gripping protrusion (72 c) ofmovable gripped part (72) moves so that it detours to the outer side ofwedge-shaped gripping protrusion (73 c) of movable gripped part (73). Asshown in FIG. 29, the rear end portion of ring-shaped member (78) passesthrough the portion of main body (71) corresponding to base end portion(72 a) of movable gripped part (72). Then, the rear end portion ofring-shaped member (78) is made to pass through the portion of main body(71) corresponding to outer side portion (72 b) of movable gripped part(72) as shown in FIG. 30.

As a result, gripping protrusion (72 c) of movable gripped part (72) andgripping protrusion (73 c) of movable gripped part (73) become locatednear the central axis of main body (71), and their positions in theaxial direction are nearly the same. Consequently, gripping protrusion(72 c) and gripping protrusion (73 c) grip or engage each other. Asshown in FIG. 31, even when ring-shaped member (78) is moved to thefront side of main body (71), the gripping state between grippingprotrusion (72 c) and gripping protrusion (73 c) is maintained. That is,the gripping state of gripping protrusion (72 c) and gripping protrusion(73 c) is maintained as long as the gripping position is not positionedaway from the central axis of main body (71) over a prescribed distance.

The length of ring-shaped member (78) in the axial direction isincreased, and as shown in FIG. 31, the rear end portion of ring-shapedmember (78) can also be located behind the gripping position betweengripping protrusion (72 c) and gripping protrusion (73 c). As a result,even when gripping protrusion (72 c) and gripping protrusion (73 c) aredisengaged from each other, because movable gripped parts (72), (73) arecovered by ring-shaped member (78), they do not protrude outwardly ofmain body (71). Consequently, the needle tip of the internal needle canbe protected and the stability becomes even higher. The operation forusing the indwelling needle having needle tip protective part (70) isthe same as that in the previously described embodiments, and will notbe explained in detail again. Also, the same functions and effects asthose in the previously described embodiments can be realized for theindwelling needle having needle tip protective part (70).

The indwelling needles of the present disclosure are not limited to theaforementioned embodiments. One can make appropriate modifications tothe embodiments. For example, in the embodiments, external needle (10)of indwelling needle A or the like indwells in the blood vessel.However, the sites for indwelling for the indwelling needle of thepresent disclosure are not limited to blood vessels. They also includeother areas in a patient's body, such as the thoracic cavity, pleuralcavity, gallbladder and liver, renal pelvis, bladder, etc. In this case,it can be used not only in feeding medicine solutions, etc., to theprescribed area in the human body, but also in removing body fluids fromthe prescribed area in the body. Also, in Embodiment 4, ring-shapedmember (78) is used and movable gripped parts (72), (73) are urged intomain body (71). However, one may also adopt a scheme in which, insteadof ring-shaped member (78), the interior of the housing is used as thepressing means. Similarly, one may also make use of the ring-shapedmember as the pressing means in Embodiments 1-3.

In addition, various materials can be used in manufacturing thepreviously described indwelling needle. For example, external needle(10), the portion other than metal needle (21) of internal needle (20),needle tip protective part (30), etc., can be made of polypropylene,polycarbonate, polyurethane, nylon, silicone, polyether imides,polyether ether ketones, ABS resins, polyethylene, and other materials.Also, cannula (11) may be made of fluororesins, polyurethane, and othermaterials. In addition, the shapes and materials for forming indwellingneedle, etc., appropriate modifications can be made within the technicalrange of the present disclosure.

1. An indwelling needle comprising: an outer cannula for indwellingplacement in a patient, said cannula having a housing attached to aproximal end thereof; an inner needle having a connection part at aproximal end thereof and a needle tip protector positioned within saidhousing and around said inner needle wherein said needle tip protectorcomprises a first portion having a sidewall defining a through-hole of afirst diameter and a second portion having a sidewall defining athrough-hole of a second diameter, smaller than said first diameter andwherein said sidewall of said first portion comprises at least oneblocking member attached thereto and inwardly movable, said inner needlehaving a tip portion and a main portion, said tip portion having alarger diameter than said main portion and wherein said tip portion,said main portion and said second portions are dimensioned such that themain portion but not said tip portion is slidable through saidthrough-hole of said second portion; and wherein said indwellingequipment is configured such that withdrawing said inner needle from thecannula in a proximal direction causes the tip portion to engage withsaid second portion, thereby withdrawing said needle tip protector fromsaid housing and causing said at least one blocking member to moveinwardly into said first portion through-hole so as to trap said tipportion therein.
 2. The indwelling needle according to claim 1, whereinsaid needle tip protector comprises at least two blocking members. 3.The indwelling needle according to claim 1, wherein said needle tipprotector comprises two blocking members diametrically opposed to oneanother.
 4. The indwelling needle according to claim 3, wherein saidhousing and said blocking members are shaped such that on withdrawingsaid inner needle, said housing is arranged to exert inward pressure onsaid blocking members causing inward movement thereof.
 5. The indwellingneedle according to claim 4, wherein said blocking members are attachedto said needle tip protector first portion sidewall at a proximal end ofsaid blocking member.
 6. The indwelling needle according to claim 5,wherein said blocking members have distal ends formed to provide alocking action when mutually engaged.
 7. The indwelling needle accordingto claim 3, wherein said needle tip protector further comprises a slipring arranged such that on withdrawal of said inner needle, said slipring is caused to slide over said blocking members to move said blockingmembers inwardly.
 8. The indwelling needle according to claim 7, whereinsaid blocking members are attached to said needle tip protector firstportion sidewall at a proximal end of said blocking member.
 9. Theindwelling needle according to claim 8, wherein said blocking membershave distal ends formed to provide a locking action when mutuallyengaged.
 10. The indwelling needle according to claim 4, wherein saidblocking members are attached to said needle tip protector first portionsidewall at a distal end of said blocking member.
 11. The indwellingneedle according to claim 10, wherein two of said blocking members haveproximal ends forming a tongue and groove interrelation.
 12. Anindwelling needle assembly comprising: an external needle comprising atubular cannula and a housing that is connected to a base end portion ofsaid cannula and has a space connected to the interior of said cannula;an internal needle comprising a tubular metal needle that has a tipportion insertable in said external needle, and a hub connected to abase end portion of said metal needle; and a needle tip protective part,which has an insertion hole into which said metal needle can be insertedand is mounted on said housing while the rear side portion of said metalneedle is inserted in said insertion hole, and which is taken out ofsaid external needle together with said internal needle while the tipportion of said metal needle is engaged in said insertion hole when saidinternal needle is pulled out of said external needle; wherein the mainbody of said needle tip protective part is formed in a cylindricalshape; on the peripheral surface of said main body, window portionsextending in the axial direction of said main body are formed on thefacing portions, respectively; and at the same time, in one of the edgeportions in the longitudinal direction of said window portions, a pairof movable gripped parts are set; one end portion of said movablegripped parts is connected by a hinge on said edge portion; when saidmetal needle is inserted in said main body, the outer side portionsprotrude out of said main body; and the other end portions are formed ongripping portions that can grip each other; and the needle tipprotective part and said external needle are arranged such that whensaid metal needle is out of the portion of said main body correspondingto said pair of movable gripped parts, the two outer side portions ofsaid pair of movable gripped parts are pressed to the internal side ofsaid main body by a pressing means, so that said two gripping portionsgrip each other, and the interior of said main body is obstructed. 13.The indwelling needle according to claim 12, wherein the innerperipheral surface of the opening portion of said housing is formed suchthat the main body of said needle tip protective part can slide, andsaid pressing means is formed on the inner peripheral surface of saidopening portion or the portion near it; when said needle tip protectivepart is positioned inside said housing, due to said metal needle, saidtwo outer side portions are energized towards the outer side of saidmain body; when said needle tip protective part is taken out of saidhousing together with said internal needle, by the inner peripheralsurface of said opening portion or the nearby portion, said two outerside portions are energized towards the inner side of said main body,and said pair of gripping portions are gripped on the tip end side ofsaid metal needle.
 14. The indwelling needle assembly according to claim12, wherein on the outer peripheral surface of the main body of saidneedle tip protective part, a ring member is set such that it can movein the axial direction, and said ring member is used to form saidpressing means; as said ring member is moved from the rear side of saidmain body to the tip side, said ring member has said two outer sideportions energized to the inner side of said main body, so that saidpair of gripping portions are gripped, and the interior of said mainbody is obstructed.
 15. The indwelling needle assembly according toclaim 12, wherein one end portion of said pair of movable gripped partsis connected to one edge portion of said window portions at positionswhich diverge from each other in the axial direction.
 16. The indwellingneedle assembly according to claim 12, wherein one of the grippingportions of said pair of movable gripped parts is formed as aprotrusion, and the other gripping portion is formed as a recess whichgrips said protrusion.
 17. An indwelling needle assembly comprising: anexternal needle comprising a tubular cannula and a housing that isconnected to the base end portion of said cannula and has a spaceconnected to the interior of said cannula, an internal needle comprisinga tubular metal needle that has a tip portion protruding from the tipopening portion of said cannula and can be inserted in said externalneedle, and a hub connected to the base end portion of said metalneedle, and a needle tip protective part, which has an insertion holeinto which the rear side portion of said metal needle can be insertedand is mounted on said housing while the rear side portion of said metalneedle is inserted in said insertion hole, and which is taken out ofsaid external needle together with said internal needle while the tipportion of said metal needle is engaged in said insertion hole when saidinternal needle is pulled out of said external needle; wherein the mainbody of said needle tip protective part is formed in a cylindricalshape; on the peripheral surface of said main body, window portionsextending in the axial direction of said main body are formed on thefacing portions, respectively; and at the same time, in one of the edgeportions in the longitudinal direction of said window portions, a pairof movable gripped parts are set; one end portion of said movablegripped parts is connected by a hinge on said edge portion; when saidmetal needle is inserted in said main body, the outer side portionsprotrude out of said main body; and the other end portions of saidmovable gripped parts are formed on flexible gripping pieces; and saidneedle tip protective part and said external needle are arranged suchthat when said metal needle is out of the portion of said main bodycorresponding to said pair of movable gripped parts, the two outer sideportions of said pair of movable gripped parts are pressed to theinternal side of said main body by a pressing means, so that said twogripping pieces grip the other edge portions of said window portions,and the interior of said main body is obstructed.
 18. The indwellingneedle assembly according to claim 17, wherein the inner peripheralsurface of the opening portion of said housing is formed such that themain body of said needle tip protective part can slide, and saidpressing means is formed on the inner peripheral surface of said openingportion or the portion near it; when said needle tip protective part ispositioned inside said housing, due to said metal needle, said two outerside portions are energized towards the outer side of said main body;when said needle tip protective part is taken out of said housingtogether with said internal needle, by the inner peripheral surface ofsaid opening portion or the nearby portion, said two outer side portionsare energized towards the inner side of said main body, and said pair ofgripping pieces grip the other edge portions of said window portions onthe tip side of said metal needle.
 19. The indwelling needle assemblyaccording to claim 17, wherein on the outer peripheral surface of themain body of said needle tip protective part, a ring member is set suchthat it can move in the axial direction, and said ring member is used toform said pressing means; as said ring member is moved from the rearside of said main body to the tip side, said ring member has said twoouter side portions energized to the inner side of said main body, sothat said pair of gripping pieces grip the other edge portions of saidwindow portions, and the interior of said main body is obstructed. 20.The indwelling needle assembly according to claim 12, wherein saidwindow portions are formed in nearly the central portion in the axialdirection of said needle tip protective part.